Statins and beta blockers are working their way into the aquatic ecosystem, according to West Virginia University researchers who have discovered evidence of the cardiovascular drugs in fish collected from two West Virginia rivers.
Joseph Kingsbury, a doctoral student in natural resources science, and Kyle Hartman, professor of wildlife and fisheries resources at the WVU Davis College of Agriculture, Natural Resources and Design, published the initial, long-term exposure effects that revealed the presence of statins and beta blockers in the fish sampled from the West Fork and Tygart Valley rivers in Weston and Elkins, respectively.
Beta blockers treat high blood pressure, while statins prevent the synthesis of cholesterol. Both are widely prescribed by physicians for heart disease and cardiovascular conditions.
Water treatment facilities, which aren’t effective at removing these variants, discharge pharmaceuticals and their derivatives back into the waterways. While the drugs do break down quickly, the popularity of these medications means facilities continuously deposit more.
Kingsbury, of Aurora, Illinois, approached the research as an emerging contaminant concern.
“With contaminants, the first place we always start is where they’re coming from,” he said. “Can we isolate those sources? Does it come from us? Not so much chemical plants, but from individual humans. We ingest the drugs, we partially digest them and then we excrete active variants.”
While humans take these medications to lower LDL cholesterol, fish produce cholesterol to store lipids.
“For us, lipids are often considered bad,” Hartman said. “But lipids get fish through the winter and lean times. I was concerned we might be seeing eroding fish populations and not really have any idea why, because it’s not outright killing them.”
The researchers looked for two types of each drug in the waterways and studied fish health relative to these pharmaceutical concentrations, both upstream and downstream of the discharge facilities, as well as within the discharge area.
Treated water is usually discharged from a straight pipe into the river. Fish congregate near the warm water flow and may utilize artificial habitats installed to help prevent erosion.
The researchers created several models to show how these drugs and concentrations change by location, as well as with different water quality parameters like temperature, pH and conductivity.
The results of this initial study revealed accumulation of certain statins in fish, some of which bioaccumulate at a much higher rate than Kingsbury and Hartman had expected.
“Pharmaceuticals are a unique contaminant designed to alter our bodies through specific chemical pathways,” Kingsbury said. “Fish are vertebrates, they have a lot of the same preserved biological pathways that we have. So, it doesn’t take a very high concentration to alter their biological systems.”
Like human livers, fish livers process toxins. Beta blockers and statins are processed in the liver and accumulate there. Kingsbury and Hartman suspected fish livers would show damage and found that, in some cases, the organs were discolored and the fish had parasites.
“None looked super healthy compared to traditional fish livers,” Kingsbury said. “And pharmaceuticals are very resilient. They’re meant to be saved, to go on our shelves and not break down over the years. We found quite a few sub-lethal effects.”
Kingsbury worked with the West Virginia Division of Natural Resources to collect fish from 21 different species in the two rivers. Kingsbury looked at organ size and organ weight as well as overall condition.
“The models showed us that certain drugs affect certain classifications of fish differently, in terms of overall health,” he said.
In addition to collaborating with WVDNR, Kingsbury worked with David Sanchez at the University of Pittsburgh’s chemistry department to develop and design a new method of detecting statins in fish. They were most interested in the statins because of the potential effects on fish eggs.
As research continues, Kingsbury will need a larger sample size to determine these effects more precisely, especially those that affect the reproductive system — eggs and embryos. While little in-depth research has previously been done on the role that statins and beta blockers might play in embryogenesis, other initial studies conducted have indicated there may be behavioral changes in the animals. At this point, however, the minimum dose to trigger such a response has not been discovered.
Kingsbury’s primary concern is not so much instantaneous exposure but continuous, long-term multigenerational exposure.
“Pharmaceuticals are notorious for altering our DNA,” he said. “Fish are no different.”
In the next phase, Kingsbury will be designing long-term exposure studies in the lab that look at chronic toxicity over multiple generations of fish. Additionally, the researchers want to refine their method of detecting the top five most popular statins in the aquatic ecosystem.
Moreover, Hartman and Kingsbury see the potential to steer physicians toward certain compounds and drugs that may be less harmful.
“We’d love to be able to help companies and those who make the decisions be more aware of what happens when they introduce these drugs to market,” Kingsbury said.
